Do you both have hernias?
Please take to heart all the advice already given about packing light. This is my favorite recent posting from the packing forum: Why didn't I listen to you, Rick? Packing Educational and funny.
This Sarah Murdoch Travel Talk, Packing Light & Right, is also an eye opener for anyone who thinks they need to take big full bags.
If you each can't manage your bags on your own, your bags are too big and you're taking too much stuff. Although my gray hair and wrinkles attracts helpers who called me Nonna in Italy, and I have accepted their advice and help on occasion, I figure that if I can't manage my luggage myself, I shouldn't be traveling the way I do.
For all my trips ranging from 3 weeks to 4 months, I've used a carry-on and a personal item. Due to contrary knees, I switched from a backpack to a roller bag a few years back. I pack for a week and do laundry along the way -- some sink washing, some DIY laundromat and some laundry service.
This year's trip will be for 5 weeks and I'll be taking this international roller bag (20.25"x14"x8" including wheels and handle, 4lbs, 9oz empty) and this cross-body bag ( 13.6"x11.8"x4," 2.2oz empty).
Both will work on the 3 intra-European flights I have if I can keep their packed weights down. One European airline says 4.4lbs for the cross-body and 17lbs for the roller bag, one says 22lbs for the 2 bags combined. I did get tickets that will allow me to check the "big" one if I fail in packing that lightly.
Many on the forum pack lighter and use smaller bags than I do. Some pack heavier and use bigger ones. You need to decide what's best for you, but you've already stated a significant reason for packing on the light side.